Dies for the manufacture of metal wheels



July 27, 1937. J. H UI I N E'r Ah V I 2,088,265 I DIES FOR THE MANUFACTURE OF METAL Patented July 27, 1937 UNITED STATES PATENT OFFICE Jules Hulin and George Ford, Nivelles, Belgium Application August 16, 1933, Serial No. 685,466

In Belgium September 8, 1932 1 Claim.

The present invention relates to dies for the manufacture of metal wheels in a single piece made from metal sheets. v

Attemps have already been made to construct metal wheels in a single piece from metal sheets by bending. and dishing the latter, but it has never been possible to carry this in practice, because of the considerable waste produced during manufacture owing to the formation of defects in the sheet metal.

In order to remedy this disadvantage, according to the invention, after having dished a metal sheet so as to convert it into a dish, the bottom of the dish is pressed towards the interior thereof by stamping.

In order to carry out this process advantageously, according to the invention, the radius of curvature of the rounded edges of the dies and punches employed for dishing is equal to about 3.6 times the thickness of the metal sheet.

Other details and features of the invention will appear in the course of the description of the accompanying drawing vwhich represents the in vention diagrammatically.

Figure 1 shows a metal sheet about to undergo the first stage of the process.

Figure 2 shows the piece obtained at the end of this first stage.

Figure 3 shows the metal sheet about to undergo the second stage of the process.

Figure 4 shows the wheel obtained at the end of this second stage.

In order to produce a metal wheel according to the invention, a metal sheet 2 (Figure 1) is placed on a dishing die 3. For-a metal sheet of one millimetre in thickness, a value equal to about 3.6 millimetres is chosen for the radius of curvature of the rounded edge 3a. The same value p is also chosen for the radius of curvature of the rounded edge .40 of the dishing punch l. The ratio between these radii of curvature and the thickness of the metal sheet to be dished is therefore very much smaller than ordinary.

The elements having been placed in the posi-' tion shown in Figure- 1, the punch is driven into the die until theposition shown in Figure 2 is reached. The ,dished metal sheet thus appears in the form of a dish 2a of a depth varying according to the dimensions of the wheel.

In order to carry out the second stage of the process, the said dish 20 is first of all placed in a stamping matrix consisting for example of two pieces 5 and 6 (Figure 3). The stamping punch 'l is then introduced into the piece 5.

55 The second stage comprises pressing the hottom of the dish 2a towards the interior thereof by stamping, so that the elements appear as shown in Figure 4. As the bottom of the dish is pressed inwardly, the lateral wall thereof is bent back within itself, as may easily be understood from the showing in Figs. 3 and 4 of the drawing. In other words, the bottom is forced partially through the cylindrical wall of the dish in a manner somewhat similar to that employed in turn- I ing an ordinary bag or sack inside out. The width of the rim of the wheel 21) represented in Fig. 4 is in fact smaller than the depth of the dish 2a represented in Fig. 3 by a quantity approximately equal to the width of the part bent back at the interior of the rim.

During the bending of the lateral wall of the dish back on itself, the upper part of the wall in Fig. 3 is pressed toward the exterior by the rounded edge Ia of the punch I in the circular groove 5a of the matrix, the diameter of which is greater than that of the part receiving the lateral wall of the dish. The diameter of the punch 1 is such that the part bent back upon itself is applied against the interior of the rim. The part which undergoes bending is in these conditions formed to enter in the groove 5a during the bending. The presence of groove 51: makes it easy to avoid the formation of cracks, wrinkles or other defects at the place where the .disc or web joins the rim. Moreover, at the end of the bending back operation groove in effects the formation of a flange 211 in the body of the wheel which advantageously reinforces it without supplemental operations. It is obvious that the form of the recess 5a andof the edge 10 of the punch will be modified according to the form to be given to the flange 2d.

The lower portion of the punch 1 is of a diameter equal to the external diameter of the cylindrical lateral wall of the blank minus four times the thickness of the sheet. The cylindrical member 6 is of a diameter equal to the diameter of the lower cylindrical part of the die minus two times the thickness of the sheet.

The wheel made according to the process herein described is covered by our copending application Serial No. 749,110, filed October 19, 1934.

The invention is not limited to the form of construction shown, and many modifications may be made in the form and constitution of the elements taking part in its construction, without departing from the scope thereof.

What we claimisr An apparatus for manufacturing a metal wheel, comprising a die, for receiving a dished blank with a cylindrical lateral wall, having a cylindrical wall of diameter equal to the external diameter of said cylindrical lateral wall or the blank and oi! a height equal to the width of the rim of the wheel to be made, said die also having above said cylindrical wall another cyllndrical wall 01' greater diameter, a punch adapted to bend a part of the said cylindrical lateral wall of the blank along and in contact with a part of the inner surface thereof, said punch having an upper cylindrical part of the same diameter as the larger cylindrical wall of the die and a lower cylindrical part oi a diameter equal to wall of the 10 

